2 stalks lemongrass, trimmed, outer layers discarded, halved lengthwise, and smashed with the side of a chef’s knife

1 Tbs. minced fresh ginger

8 large fresh torn basil leaves; plus sprigs for garnish

½ cup fresh cilantro leaves, for garnish (optional)

9 oz. fresh udon noodles

1 medium lime, half juiced and half cut into wedges

2 tsp. packed light brown sugar

Heat 1-1/2 Tbs. of the oil in a 5- to 6-quart Dutch oven over medium-high heat until shimmering hot. Season the chicken with 1/2 tsp. each salt and pepper, and cook without disturbing until it’s browned and releases easily from the bottom of the pot, about 2 minutes. Flip and cook until the secon...